This invention relates generally to diagnostic ultrasound systems. In particular, the present invention relates to method and apparatus for interactively detecting the contour of an object.
Various algorithms are available which search for the outside edge, or contour of an object, within an image. These algorithms may be used to calculate various size dimensions of the object. For example, the object may be an organ, cyst, or tumor which the user is interested in further analyzing to determine proper treatment.
Problems exist with the current algorithms and user interface methods, however. For example, a user may select a single starting point within an object. The algorithm starts with the single starting point and searches outward looking for changes within the tissue which identify boundaries between different types of tissue. Another method is to employ known shapes, such as circles and ovals, then require the user to drag the contour to the desired location around the object. Still another method has the user draw the contour of the object using a mouse or various keyboard keys, which can be quite time consuming, with accuracy being affected by the display size and resolution, and the minimum distance the user may move the cursor on the display. Also, working with 3D images adds an additional element of complexity.
Additionally, tissue in the body is not uniform. High contrast boundaries exist between different types of tissue, such as bone and muscle, and muscle and blood. Lower contrast boundaries exist also, such as a change within the density of the muscle, organ, or tumor. An automatic searching algorithm may detect a boundary close to the starting point which does not reflect the contour of the object, and thus exclude portions the object. Alternatively, the algorithm may search for a boundary having a greater contrast and include areas which are outside the object.
Thus, a system and method are desired to obtain a contour of an object within an image that addresses the problems noted above and others previously experienced.